Disk drives are information storage devices that utilize at least one rotatable disk with concentric data tracks containing the information, a transducer (or head) for reading data from or writing data to the various tracks, and a transducer positioning actuator connected to the transducer for moving it to the desired track and maintaining it over the track during read and write operations. The transducer is attached to a slider, such as an air-bearing slider, which is supported adjacent to the data surface of the disk by a cushion of air generated by the rotating disk. The transducer can also be attached to a contact-recording type slider. In either case, the slider is connected to a support arm of the transducer-positioning actuator by means of a suspension.
The suspension must meet several requirements. The suspension must be flexible and provide a bias force in the vertical direction. This is necessary to provide a compensating force to the lifting force of the air bearing in order to keep the slider at the correct height above the disk. Also, vertical flexibility is needed to allow the slider to be loaded and unloaded away from the disk. Another requirement of the suspension is that it must provide a pivotal connection for the slider. Irregularities in operation may result in misalignment of the slider. The slider is able to compensate for these problems by pitching and/or rolling slightly to maintain the proper orientation necessary for the air bearing. Another requirement of the suspension is that it must be rigid in the lateral direction. This is needed to prevent the head from moving side to side, which would result in the head reading the wrong track. Rigidity is also required to maintain slider position during high lateral shock events such as crash stop so that it does not slam into other parts of a disk drive.
As disk drives have become smaller in size, the recorded track density has increased dramatically. This has necessitated the use of smaller and smaller heads and suspensions. However, these smaller geometries of the suspension and head make manufacture much more difficult. In particular, when moving from a Pico slider to a Femto slider, flexure pitch and roll stiffness and suspension spring rate have been reduced significantly. At the same time it is desirable to continue to use the same Stainless Steel thickness for a Femto flexure as for a Pico flexure due to proven manufacture yield. As a result, it is difficult to maintain acceptable lateral stiffness of the flexure. What is needed is a suspension design and method of manufacture that lends itself to reduced pitch and roll stiffness while simultaneously maintaining acceptable lateral stiffness.